Unit 2 Review: True or False, Salt (NaCl) is a pure substance and an element?

1. Unit 2 Review

2. TRUE or FALSE Salt (NaCl) is a pure substance and an element.

3. ANSWER • False… pure substance and compound. • Two elements combined = compound

4. Which state of matter would take the shape of it’s container and has a fixed/definite volume?

5. ANSWER • Liquid

6. A popsicle melting on the sidewalk is an example of what type of change?

7. ANSWER • Physical…all phase changes (solid  liquid  gas) are physical changes.

8. “A shiny piece of steel rusted from sitting out in the rain.” • Which part of this statement represents a physical property? Which part represents a chemical property?

9. ANSWER • “A shiny piece of steel rusted from sitting out in the rain.” • “SHINY” is physical, describing what it looks like • “RUSTING” is chemical, because rust has a different composition than steel.

10. Matter changing from its liquid state to its gaseous state is called ______.

11. ANSWER • Vaporization • Boiling • Evaporation

12. What is an ion?

13. ANSWER • An atom with a positive or negative charge. • An atom that has lost or gained electrons.

14. If at ion has a positive charge, did it GAIN electrons or LOSE electrons?

15. ANSWER • LOSE electrons so that the there are now more positive protons than there are negative electrons.

16. What charge would group 7 most likely have?

17. ANSWER • -1

18. What charge would group 2 most likely have?

19. ANSWER • +2

20. How many neutrons does Carbon-14 have?

21. ANSWER • 14 is the mass number of that particular isotope of Carbon and the atomic number of Carbon is 6, so 14-6= 8 neutrons.

22. TRUE or FALSE To get an isotope, you fluctuate the number of electrons.

23. ANSWER • FALSE. You would fluctuate the number of neutrons to change the mass.

24. Who discovered protons and how? FIRST AND LAST NAME, BE DETAILED.

25. ANSWER • Ernest Rutherford by shooting alpha particles (positive particles) at a piece of foil. The alpha particles deflected, which showed they were hitting something else that was positive (protons).

26. Who came up with the first atomic theory? FIRST AND LAST NAME.

27. ANSWER • John Dalton

28. Who discovered electrons and how? FIRST AND LAST NAME. BE DETAILED.

29. ANSWER • JJ Thomson- cathode ray tube showed electrons are emitted. Negative side of magnet repelled (or positive side attracted) so proved they were negative.

30. What part of the atom gives it it’s identity?

31. ANSWER • Protons

32. Would spaghetti be a pure substance or a mixture?

33. ANSWER • Mixture (heterogeneous)

34. What are the 3 particles of the atom and their respective charges?

35. ANSWER • Proton + • Neutron (neutral) • Electron -

36. Why isn’t the mass of strontium-52 on the periodic table reported as 52?

37. ANSWER • The periodic table shows average atomic masses of all isotopes present

38. How many electrons fit on energy level 1, 2,& 3?

39. ANSWER • 1st holds 2 • 2nd holds 8 • 3rd holds 8

40. Who created the atom model where electrons are found on energy levels?

41. ANSWER • Niels Bohr

42. Draw the Bohr diagram for phosphorus.

43. ANSWER • 15 P • 16 N • 15 E

44. Write the following info in isotopic notation • Protons- 26 • Neutrons- 31 • Electrons- 23

45. ANSWER • 57Fe3+ 26

46. Atomic Number Mass Number Neutrons Electrons

47. ANSWER • Atomic Number- 16 • Mass Number- 33 • Neutrons- 17 • Electrons -18

48. Who discovered the neutron? FIRST AND LAST NAME.

49. ANSWER • James Chadwick

50. Protons-20 • Electrons-20 • Neutrons-22 • Isotope name?